This study was carried out to investigate the chemical characteristics of rainwater sampled in Cheju City from July 1994 to June 1996. Concentrations of major Ions (Cl^-, SO_4^2-,NO_3^-, Na^+, K^+, Ca^2+, Mg^2+ and NH_4^+) were determined. The pH of rainwater, calculated from the volume weighted H^+ concentration, was found to be 5.61, indicating extensive neutralization of the acidity in the rain. The relative magnitude of average ionic concentrations followed the relation Cl^-> SO_4^2-> Na^+> Ca^2+> NH_4^+> NO_3^-> Mg^2+> K^+. The ions associated with sea salt, namely Na^+ and Cl^-, dominated the total concentration of ions in the rainwater and the SO_4^2- ion accounts for 20% of total concentration. [H^+]/[nss-SO_4^2-+NO_3] ratio and a multiple regression for SO_4^2- and NO_3^- ions against H^+, Ca^2+ and NH_4^suggested that all of SO_4^2+ and NO_3^- in rainwater was not necessarily associated with H_2SO_4, anf HNO_3, but might also occur in combination with NH_4^+ or Ca^2+. The monthly mean concentrations of SO_4^2-, Ca^2+ and NH_4^+ in spring time was higher than those in other seasons. These results may be attributed to the fertilizer application as the local sources and the yellow sand phenomina as a regional-scale sources.

The conditions of cold stroage of Citrus unshiu Marc. var. okitsu produced in Cheju were investigated. The changes of peel moisture contents soluble solids, total sugar, vitamin C and density were slightly occured, and decay ratio was below 20% on keeping freshness relatively till late of March during cold storage. After thats decayed citrus fruits were increased gradually mainly from cold injury with lower temperature and high humidity. The loss of fruit weight, decrease of fruit hardness, and decrease of acid content were occured gradually during cold stroage. Because of the difficulty of long term storage for Citrus unshiu, the conditions and periods of cold storage would be determined after considering the physicochemical properties of fruits every year.

Total carotenoid contents, color values and spectrum characterization in the range of UV of fruit juice and organic acid and free sugar contents determined by HPLC were investigated on 10 varieties of Cheju citrus fruits. Carotenoid contents of juice were 0.47-9.20/ml which showed higher with Dangyooja while showed lowest content with Meiwa Kumquat. Lightness (L) of juice was highest in Meiwa Kumquat, and in the order of Sankyool, Navel orange and Hungjin. Redness(a) and yellowness(b) were in the order of Dangyooja, Natsudaidai, Sambokam and Kinkoji. The maximum absorption wavelengths if citrus Juices were variable at 269.5-285.5nm according to varieties and it was observed that were changed by mixing with Juices of other varieties. Major organic acids of citrus juice were citric and malic acid, and citric acid was 64.4-95.1% of total organic acids. Ascorbic acid was high in Navel orange, Sudachi and Dangyooja, and low in Meiwa Kumquat and Hungjin. Major free sugars were sucrose, glucose and fructose. Sucrose was 49.2-75.2% of total free sugars, and high in Sankyool and Meiwa Kumquat. Glucose and fructose were high in Meiwa Kumquat and Navel Orange.

Physicochemical properties and the conditions of cold storage of kiyomi clangor(Citrus unshiu x sinensis) produced in Cheju were investigated. Firmness, edible part ratio, soluble solids, and acid content were decreased gradually with incurasing fruit size. Carbohydrates in juice were consisted of 65.12% sucrose, 19.65% fructose, and 15.23% glucose The main organic acrid In juice was 57.4% of citric acid, and others were lactic acid, malic acid, oxalic acid and fumaric acid, respectively. Weight loss were occured very. slowly to about 6% till late of May, but decayed fruits were occurred very slowly to about 6% till late of May, but decayed fruits were arisen to about 8% at 3, and about 13% at 5 of storage temperature. The changes of peel moisture content, soluble solids, total sugar, vitaamin C, and density of fruits were slightly occured during cold storage. Cold storage at 3 and 87% relative humidity kept freshness of citrus fruits for a long-term without damage of cold injury.

Total carbohydrates of Kumquats was 14.69% Kumquats, Citrus natsudaidai, and C. platgmama contained 18.3, 11.1 and 13.0%, of soluble solids, and 42.39, 32.09 and 20.13mg/100g, of vitamin C, respectively. Acid contents of C. natsudaidai and C. plafmama harvested on March 1995 in south Cheju were 2.52% and 0.89% . In preparing of Kumquats-tea, combination of 50% honey and sugar, 5% oligo-sugar, 32% Kumquats slice, 13% juice of C. natsudaidai were the best recipe for sensory evaluation. In C. natsudaidai-tea, combination of 5∼10% peel slice treated at 90 for 1min, 50∼60% concentration of sugar and 35∼40% of flesh of C. natsudaidai were good. for sensory evaluation. Microbial growth was not observed in the sterilized products for more than one month at 30.

This study was conducted for the efficient utilization of a scoria, which is abundantly found in Cheju island, as adsorbent and the scoria was examined for its performance in clarification of adsorption of heavy metal ions. The order in heavy metal ions adsorbed on scoria was; Pb^+>Cd^2+>Cu^2+>Ag^+>Co^2+>Zn^2+>Cr^3+>Cr^6+. This tendency was relatively consistent with the decreasing order of radius of hydrated metal ion. Also, the smaller scoria size and the larger amounts of scoria showed higher removal efficiency for heavy metal ions. The same scoria size showed more effective removal efficiency for heavy metal ions at lower initial concentration than at higher initial concentration. The adsorption abilities of original scoria and chemically treated scoria were compared. Adsorption isotherm of scoria was generally obeyed to Freundlich formula than Langmuir formula and Freundlich constant, 1/n was obtained in the range of 0.2∼0.4.

In order to determine the quality of Citrus unshiu(medium cultivar of satsuma mandarin) produced in Cheju, citrus fruits sampled at sorting places and harvested directly on citrus tree in south and north area of Cheju were analyzed. The fruits were grown in size till early of November, and soluble solids were increased continuously after that. Compared with the quality of citrus fruits as a factor of soluble solids, firmness, total sugar, pH, and color index, the optimum harvest periods were supposed to be reasonable from early of December for C. unshiu Marc. var. yonezawa and C. unshiu Marc. var. hayashi, Fruit weights and peel thickness had a linear correlation with increasing fruit size, but soluble solids and acid contents had not a correlation. The selection of C. unshiu variety was needed to determine by the properties of storage.

Surface heat balance of the northern sea of Cheju Island for summer in 1993 and 1994 is analyzed using the observation data obtained by Marine Research Institute, Cheju National University. Each flux elements at the sea surface is derived from the marine meteorological reports with application of an aerodynamical bulk method for the turbulent heat fluxes, and empirical formulae for the long-wave radiation heat fluxes. The flux divergence of oceanic heat transport and the rate of heat storage in the ocean are estimated as residual. The features of the surface heat balance are mainly decided by the solar radiation flux and the latent heat flux for 1994. But the Bowen Ratios were large for 1993. This means that the sensible heat fluxes were nearly equal to the latent heat fluxes for 1993. In this period, mean flux divergence of oceanic heat transport is about 130 W/㎡.

Soluble solids and total carbohydrates of Citrus miyakawa wase harvested middle of November 1993 Topyung-Dong, Seogwipo-si, and Cheju were 10.7 and 8.57%, and carbohydrate was consisted of about 1/2 sucrose, 1/4 glucose and 1/4 fructose, respectively. Acid content of citrus Juice was 1.04%, and citric acid was 74.27% of total organic acids. Fruit weight, peel thickness, soluble solids, pH, hardness and edible part ratio had a good correlation in linear function with increasing fruit size. Total carbohydrate, reducing sugar and vitamin C of citrus jam made on optimum conditions were 65.33%, 27.98%, and 51.40mg/100g , respectively. Microbial growth on the products were not recognized at 3 for a month. Compared with other related citrus jellying products, the test sample was excellent in appear ance, taste and total preference degree on sensory evaluation.

The groundwater levels at 11 sites and the vertical variations of the water quality at 1 site were measured to study the characteristic of the groundwater level fluctuation of Cheju Island. The results of the measurements for the groundwater levels were as follows; In the eastern part, inculding Kimnyong, Jongdal and Sungsan, a sinusoidal fluctuation of groundwater levels occured in response to oceanic tides. The tidal effect on the groundwater level was reduced depending upon the distance from seashore. But time lag showed that the trend is reversed. However, in the Samyang, Kosan and Shinhyo areas show that the groundwater level was directly influenced by the amount of precipitation. Especially, Shinhyo area which southern part in Cheju was affected the most and show upper parabasal groundwater level. In Susan-I which eastern part in Cheju, well revealed that water quality changed with the period of a tide. Salinity at the 11m, bellow the natural groundwater level, was approched to the brackish groundwater(1000ppm).

Soluble solids(Brix), acid content and edible part ratio of Citrus unshiu collected at sorting Places in south Cheju area wee more lowered, and peel thickness was more thickened with increasing fruit size. Compared to early variety of Citurs unshiu(C. unshiu Miyakawa Mar), peel thickness of medium variety of Citurs unshiu(C. unshiu Hayashi Mar) was more thickened, and edible part ratio was more lowered with increasing fruit size. Soluble solids of medium variety of Citurs unshiu were lowered, and acid contents were increased compared to early variety. Processing properties for pressing concentrated juice was good for early variety of Citurs unshiu, especially on fruit diameter of 50-65mm. Soluble solids, acid contents and juice ratio were decreased with increasing peel thickness. The quality properties for fresh fruit with peel thickness had a good correlation on early variety of Citurs unshiu, and these data are supposed to be applied to the quality evaluation of Citurs unshiu produced in Cheju.

제주지방에 있어서 쌀보리와 맥주보리의 청초 및 종실 겸용재배에 알맞은 파종기, 파종량, 시비량, 청초이용기간 등을 밝히고자 쌀보리(새쌀보리)와 맥주보리(두산 22호)를 공시하여 시험한 결과를 요약하면 다음과 같다. 1. 새쌀보리는 파종기, 파종량, 시비량, 청예시기에 관계없이 청예후 100% 생존하였으나 조파한 두산 22호는 증파, 증비할수록 1~2월에 예취시 청예후 생존율이 떨어졌다. 2. 두 품종 모두 조파할수록, 청예종기가 늦을수록 청초수량이 많았다. 증파, 증비함에 따라 청초수량이 증가하는 경향이었다. 3. 건초의 조회분 및 조지방은 파종량, 시비량, 청예시기 등에 따른 차이가 없었으나 조단백질은 증비할수록 증가되었고 청예시기가 늦을수록 감소되었다. 가용생무질소물은 층예시기가 늦어짐에 따라 증가하였고 증비에 의해 감소되는 경향이었다. 4. 조파할수록 일찍 출수 및 성숙되었다. 청예에 의한 출수지연이 새쌀보리에서느 적었으나 두산 22호에서는 매우 컸었고 조파할수록, 정예종기가 늦을수록 정예에 의한 출수지연이 컸었다. 증비에 의해 두산 22호의 성숙기가 3~5일 지연되었다. 5. 새쌀보리에서 보다 두산 22호에서 청예에 의한 간장단축이 컸었고 두 품종 모두 청예종기가 늦을수록 간장이 작아졌다. 6. m2 당 수수 및 수당입수가 새쌀보리에서는 청예에 의하여 감소되지 않았지만 두산 22호에서는 청예종기가 늦어질 경우 감소되었다. 7. 두 품종 모두 청예종기가 늦어짐에 따라 종실수량이 감소되었으나 새쌀보리에서는 청예종기가 2월 27일이어도 6~11%의 감수에 그치었다. 두산 22호에서는 12월 28일 이후 예취에 의하여 종실수량이 6~66% 감소되었다. 청예후 종실수량은 파종량과 시비량에 따른 차이가 없었다. 8. 제주지방에서 쌀보리와 맥주보리를 9월 중순부터 10월 중순까지 파종하여 10월 하순부터 2월 중순(맥주보리 12월 하순)까지 방목에 이용하여도 적절히 관리할 경우 관행재배와 비슷한 종실수량을 얻을 수 있는 것으로 보여진다.

본 연구는 제주도 개량목초지에서 1971～1978 연까지의 식생의 연차적민 변화과정을 조사한 결과로서 그 개요는 다음과 같다. 1. 식생은 1～3연초지에서는 Dactylis glomerata / Trifolium repens type, 4연초지에서 Imperata cylindrica / Trifolium repens type, 5～8연초지에서는 Imperata cylindrica / Zoysia japonica type으로 변화하였다. 2. 초장의 변화과정에서 혼파목초들은 1～3연초지까지는 길어지고 있으나(37.9～45.1cm) 그 이후부터 매년 짧아지고 있는 반면 잡초류의 초장은 1연초지 이후부터 현저히 길어지고 있는(30～44.2cm) 경향이었다. 3. 피도에 있어서 혼파목초들은 1 연초지에서 72.4％이던것이 해가 지남에 따라 극히 감소되어 8연초지에서는 0.2％로 나타나는 반면 잡초들은 1연초지 이후부터 현저히 증가되었다. 4. 연수의 경과에 따르는 식생구성률의 변화는 피도와 비슷한 경향이었다. 5. 초장 및 피도, 식생구성률에 있어서 해가 경과함에 따라 현저히 증가되는 식물은 Imperata cylindrica, Zoysia japonica, Miscanthus sinensis, Pteridium aquilinum, Crisium japonicum, Artemisia japonica 등이고 Cetella asiatica, Digitaria sanguinalis, Artemisia asiatica 등은 오히려 감소되었다. 6. 혼파목초지에 침범한 잡초유는 1연초지에서 24종이었으나 해가 경과함에 따라 종수가 증가되어 6연초지에서는 60종이었으며 그중 가축의 불식초류가 매년 증가되는 경향이었다.

제주도 화산회토 신개간지에 있어서 숙전화를 촉진시키는 한가지 방법으로서 적응력이 강하고 잡초의 재생을 억제하는 능력이 강한 두과작물을 선택하고자 알팔파, 화이트클로버, 채두, 완두, 대두 및 차풀 등의 6개 두과작물을 공시하여 이들의 근류착생 정도를 조사하고 이중 근류착생이 가장 양호하였던 차풀의 잡초와의 경합관계를 조사한 결과는 다음과 같다. 1. 착생된 근류의 무게는 차풀에서 가장 무거웠고 다음은 완두, 대두, 화이트클로버, 채두 및 알팔파의 순이었다. (알팔파는 관찰 불가) 2. 자연초지에 차풀을 파종할 경우 그 건물중은 4년차까지 거의 직선적으로 증가하였으나 띠는 3년차 부터 감소하는 경향이었다. 3. 제주도 지방의 신개간지에서는 지력증진을 위해서 차풀을 재식하는 것이 유리할 것으로 추론되었다.